Electromagnetic apparatus



8- 4, 1970 L. F. CRAEMER ETAL 3,523, 3 ELECTROMAGNETIC APPARATUS Filed Jan. 12, 1968 COIL 34 4o Y f INVENTORS LAMBERT F- CRAEMER SAMUEL r. KELLY W/LL/AM W. CHAMBERS JAMES R. W/LLSO/V [ATTORNEYS United States Patent Oflice 3,523,263 Patented Aug. 4, 1970 ware Filed Jan. 12, 1968, Ser. No. 697,411 Int. Cl. H01f 7/08, 7/14 US. Cl. 335-276 6 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic apparatus composed of a magnetizable core having a flat and a round pole leg, with an energizing coil thereon, a flat armature arranged transversely of the coplanar outer sides of the legs and rollingly fulcrumed on the round leg, with only single line rotational friction therebetween, for pivotal movement in a curvilinear path normal of the pole faces and transversely of the axes of the legs, about an axis paralleling such leg axes, into facial contact with the flat leg; and positioner tabs on the armature cooperating with the adjacent part on the round leg upon antagonistic springurged movement of the armature and, upon energizing, a gap occurring between the tabs and such leg.

BACKGROUND OF THE INVENTION The present invention generally relates to an electromagnetic system or assemblage of the type essentially consisting of a magnetizable core surrounded by a winding and a permanent magnetic armature pivoting about an axis into one pivotal position, when the core is energized,'and' into another pivotal position, when the core is deenergized, the latter position being etfectuated by antagonistic return forces. In particular, the instant invention is directed to a novel electromagnet of the bipolar type with an armature pivotally associated directly with one of the legs of the core member and movable into surface contact with the other core leg.

In conventional electromagnet and armature arrangements, the pivotal movement of the armature, induced by energization and deenergization of the core in association with an antagonistic return force, is in a transitional plane parallel to the plane of the pole faces or the legs of the magnet core. Usually, the armature is movably mounted on a support member and is moved, either in an inhibited rectilinear path or in a pivotal curvilinear path, into and away from engagement wth the pole faces of the magnet core of an electromagnet, constituted by the core and an energizing winding thereon, whenever the electromagnet is energized or deenergized. When the electromagnet is deenergized, the armature is moved away from th core by antagonistic return forces, usually spring means in a plane parallel to the plane of the pole faces.

In some electromagnetic structures, it has been known to provide an armature fulcrumed across both leg poles of a horseshoe electromagnetic core and attracted toward both poles upon energization of the electromagnet, the armature movement being in a plane parallel to the plane of the pole legs.

The principal difficulties associated with such known constructions reside in the weak pull movement upon the armature by the electromagnet in relation to the size and shape of the armature, as may be dictated by a particular operating environment, the absence of full surface engagement of the armature plate with the core, and the complex mechanical assemblies of the core and armature with the consequent inability of such assemblies to be adaptable for meeting the requirements of compact or miniaturized devices dictated by modern technological practices.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simple electromagnetic arrangement wherein an armature is pivotally mounted directly on a core for easily and smoothly induced pivotal movement of the armature upon energization of the core with full surface contact between the armature and the attracting pole of the core being obtained.

Another object of the present invention is to construct an electromagnetic core with a round core leg and a flat formed attracting pole leg, with the circular outer surface of the round core leg utilized as a rolling fulcrum for an armature that moves into and out of full surface contact with the attracting pole leg. The armature pivotal movement is transverse to the pole faces on the ends of the legs and to the plane in which the legs are disposed. Such pivotal movement is about a pivotal axis which is parallel with the longitudinal axes of the legs of the core.

A further object of the present invention is to provide a fulcrum positioning means for mounting the armature plate on the round leg of the U-shaped core, such positioning means, when the electromagnet is deenergized, engaging the adjacent part of the round leg and, upon energization, a gap occurring between the positioning means and the round core leg, whereby an etfective and proper positioning of the armature is obtained with minimal interrelated friction between the armature and the mounting core leg.

In practicing the invention, and electromagnetic device is composed of a magnetizable core and an electric winding for energizing the core, a pair of pole legs defined by the core having pole end portions disposed in a plane parallel with the longitudinal axes of the pole legs, an armature disposed transversly of the pole end portions and pivotally mounted on one pole end portion for movement transversely of the plane of the pole end portions into surface contact with the other pole end portion when the core is energized, and a pivot axis for the armature being parallel to the longitudinal axes of the pole legs.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the electromagnetic system embodying to the invention;

FIG. 2 is an elevational view of the opposite side thereof;

FIG. 3 represents an end elevational view with the armature shown in the attracted position;

FIG. 4 is a view, similiar to FIG. 3, but showing the armature in a position disengaged from the attracting pole of the core; and,

FIGS. 5 and 6 diagrammatically represent end elevational views of the electromagnetic system showing the armature in engaged and disengaged positions, respectively- DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the accompanying drawing, an electromagnetic apparatus 10 includes a magnetizable core member 12 surrounded by a winding 14 and a permanent magnetic armature 16 which moves pivotally relative to the core member. The core member 12 is a U-shaped core of magnetic material having a pair of parallel legs 18 and 20. The energizing coil 14 is wound about the leg 18 and is connected to an appropriate source of electrical power through a known control arrangement (not shown). The core legs 18 and 20 terminate in free leg portions 22 and 24, respectively, which constitute pole end portions of the core and which terminate in pole faces 26 and 28.

The pole leg portion 22 is round, while the confronting, spaced, companion pole leg portion 24 is non-circular in cross-section and constitutes a fiat formed attracting pole. As shown, the legs 18 and 20 are round, with the pole end portion 24 being flattened out so that it is T-shaped in cross-section. The pole end portion 24 defines an attracting pole and has a flat outer side surface 30 which lies in a plane designated by the line y-y. The line yy touches the outer circular side surface 32 of the round pole portion. Thus, the flat side surface 30 of the attracting pole leg portion 24 and the circular side surface 32 of the round leg portion 22 lie in a common plane designated by the line y-y.

The armature 16 is in the form of a substantially flat rectangular plate, which is made of magnetic material, and is of a length greater than the transverse distance or space between the confronting pole leg portions of the core 12. The armature plate is provided with a flat rectangular face 34 which has a transverse portion 36 in line facial bearing engagement with the circular side surface 32 of the round pole leg portion 22. The armature is positioned transversely across the leg portions with the bearing portion 36 thereof fulcrumed on the circular side surface of the round pole portion 22. A transverse portion 38 of the armature face 34, adjacent one end 40 of the armature plate 16, is adapted to bear in full facial engagement or surface contact with the flat surface 30 of the attracting pole leg portion 24 of the core 12, when the core is energized.

A coil spring 42 is provided to impose an antogonistic return force on the armature 16, when the electromagnet is deenergized. The spring 42 is anchored at one end, as at 44, to a fixed support 46 and is affixed at its other end, as at 48, to the armature plate at the end portion 50 thereof, the end portion 50 extending away from the round core leg 22 in a direction opposite from the flat core leg 24. Thus, the spring 42 exerts a pull on the armature plate on the opposite side of the fulcrum line from the contacting end portion 40 of the armature plate.

The opposite face 52 of the armature plate, at the end portion 40, is adapted to abut an actuator 54 which is controlled by the electromagnetic system and which may be a part of any suitable electrical or electro-mechanical assembly. For example, the actuator 54 may be a valve in a valve assembly with the armature 16 functioning as a valve lever. The actuator 54 also serves as a stop for the armature in its pivotal swinging movement under the urgement of the spring 42, when the electromagnet is deenergized.

The transverse line portion 36 on the armature face 34 bears on the circular outer side surface of the round leg portion 22, which constitutes a fulcrum across which the armature rolls in executing its pivotal transitional movement between the contact face 30 of the attracting pole leg porion 24 and the arresting actuator 54. The round core fulcrum arrangement, involving the fiat face portion 36 of the armature plate and the circular outer side 32 of the round leg portion 22, and the fiat formed attracting pole 22 function to ensure a smooth, efficient energizing operation. The armature 16, in its pivotal transitional movement, swings about an axis, which is designated by the line x--x. As shown, the pivot axis is parallel to the longitudinal axes of the pole leg portions 22 and 24. Thus, the armature movement is in a plane transverse to the plane of both legs 18 and and their associated pole leg portions 22 and 24. The armature moves in a curvilinear path normal to the pole faces 26 and 28 and transversely of the plane in which the leg portions 22 and 24 lie. As can be seen from FIGS. 3-6, the coplanar outer side surfaces and 32 of the pole leg portions 22 and 24 lie in the common plane y-y and the pivotal axis xx of the armature plate transversely intersects such plane line y-y.

The movement of the armature 16 on the round pole leg portion 22 involves only single line rotational friction on the round pole portion. To secure proper positioning of the armature plate 16 on the round pole portion with minimal friction, a fulcrum positioner means 56 is provided. As illustrated, the fulcrum positioner means is carried by the armature plate 16 and is functionally interrelated with the round pole leg portion. Such means includes tabs 58 which are stuck out from the opposing side edges 60 and 62 of the armature plate. The integral tabs are spaced apart transversely of the armature plate and extend perpendicularly from the face 34 of the armature. The tabs are adapted to engage the adjoining part of the round pole leg portion 22 when the electromagnet is deenergized, as shown in FIG. 4 and 6.

The tabs 58 engage the surface portion 64 of the core leg portion 22; such portion 64 lying at right angles to the outer side surface 32 and confronting the tabs. Upon energization of the electromagnet and consequent attracted movement of the armature 16, a gap 66 occurs between the positioner tabs 58 and the round core leg 22, which provides a rolling fulcrum for the armature. There is a complete absence of any sliding friction on the tabs. Because of the creation of the gap 66, the positioning means 56 functions effectively with essentially only single line rotational friction on the round pole leg portion 22 of the core 12.

From a consideration of FIGS. 5 and 6, the attracted movement of the armature 16 toward and into surface contact with the attracting pole leg portion 24, when the core 12 is energized by the coil 14, can be appreciated. It is to be noted that the gap 66 occurs between the positioner tabs 58 and th eround core leg portion 22, which provides a rolling fulcrum for the anrnature. The face portion 36 of the armature plate 16 rolls about the circular side surface 32 of the round leg portion 22. There is a minimum of frictional resistance to the pivotal movement of the armature, thus ensuring that a quick and steady pull is exerted on the armature when the core is energized whereby the armature snaps into contact with the attracting pole end portion 24. The transverse portion 38 of the armature face engages the outer flat side 30 of the attracting pole leg portion 24 in full facial or surface contact, as can be seen in FIG. 5, so that a wide range contact is realized.

When the core is deenergized, the spring 42 then pulls the armature 16 away from hte attracting pole leg portion 24, with the armature rolling about the round core leg portion 22 and the positioner tabs 58 serving to position the armature, the armature, as shown in FIG. 6. The armature abuts the actuator 54, which is shown by way of example only, for the provision thereof is only incidental to the operation of the electromagnetic apparatus 10.

The electromagnetic apparatus 10 can be employed in any assembly where it is necessary or desirable to utilize an electromagnet and armature with the novel structure and functional interrelationship of the core and armature being of particular value in modern compact or miniaturized installations where space is at a premium.

"Inasmuch as the present invention is subject to many modifications, variations and changes in details, it is intended that all matter contained in the foregoing description or shown on the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An electromagnetic apparatus comprising a magnetizable core,

an electric winding on said core,

said core having a pair of pole legs disposed in spaced parallel relation to each other, each of said pole legs having a pole end portion with a surface adapted for cooperation with an armature, an armture disposed transversely across said pole end portions, a first part of said armature movable into and out of engagement with the surface on one of said pole end portions,

a second part of said armature supported on the surface of the other of said pole end portions, the said surface of the other of said pole end portions defining a rounded surface and the said second part of said armature defining a flat face rollingly bearing on said rounded surface whereby said armature is pivotally supported thereon for movement in response to energization and dcenergization of said core, and

positioning means between said armature and said core to limit movment of said armature when said core is deenergized.

2. The invention of claim 1 'wherien said positioning means is carried by the anmature and extends perpendi cularly thereof adjacent a transverse portion of the flat face and is engageable with an adjacent part of the said other pole end portion.

3. The invention of claim 2 wherein said positioning means includes tabs formed on the side edges of the armature and engaging the part of said other pole end portion substantially at right angles to the rounded surface thereof when the core is deenergized, said tabs being gapped from the said other pole end portion when the core is energized,

4. The invention of claim '3 wherein an antagonistic return force means is connected to the armature for moving the armature away from the surface on said one pole end portion upon deenergization of the core.

5. The invention of claim 1 wherein the said other pole end portion is round and the armature is a flat piece having an end fulcrumed on the round end portion, the other pole end portion being flat with the armature being moved into facial surface contact therewith when the core is energized.

6. The invention of claim 5 wherein said positioning means includes positioning tabs formed on the armature perpendicularly thereof and engaging the round end portion when the core is deenergized and, upon energization, a gap occurs between the tabs and the round end portion.

References Cited UNITED STATES PATENTS 3,183,324 5/1965 Smith 335-276 XR 3,167,693 1/1965 Hayward 335-270 3,102,974 9/1963 Williams 335274 2,891,199 6/ 19'59 Ugon 335-269 BERNARD A. GILHEANY, Primary Examiner DEWITT M. MORGAN, Assistant Examiner US. 01. x3, 33s-279, 231 

